Improvement in heating-furnaces



2 sheets-sheet 1. W. S. MGKENNA.

- Heating-Furnace. No. 196,534 Patented Oct. 30,1877.

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W. S. MGKENNA. Heating-Furnace. No. 196,534 Patenred Oct. 30, 1877.

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UNITED STATES PATENT C i:rfs1cJEo WILLIAM S. MGKENNA, OF PITTSBURG,PENNSYLVANIA.

IMPROVEMENT `IN HEATING-FURNACES.

Specification forming part of Letters Patent No. 196,534, dated October30, 1877; application filed .October 23, 1876.

To all whom 'it may concern Be it known that I, WILLIAM SMCKENNA, ofPittsburg, Pennsylvania, have invented a new and useful Improvement inHeating or Tending Furnaces, which improvement is fully set forth in thefollowing specification, reference being had to the accompanyingdrawing.

Similar letters of reference indicate corresponding parts.

My invention relates to th at class of furnaces known as heating ortending furnaces, for heating nail-plates preparatory to cutting thesame into nails, and for other like purposes; and the invention,consists, mainly in the novel construction of the iues with relation tothe heating-hearth, by which the heat is regulatedv and maintained atthe desired degree with great economy of fuel, obviating the objection,heretofore observed in heating-furnaces, of the sudden cooling of thesaine when the doors were opened forplacing or removing the plates.

Reference is hereby made to the accompanying drawings,'in which Figurelis an isometrical perspective view. Fig. 2 is a top view, with thecovering-arch removed. Fig. 3 is a plan view, with the heating-hearthremoved. Fig. 4 is a vertical transverse section; and Fig. 5is a viewshowing longitudinal sections, one through the center of the furnace,and one insideof exterior walls.

AA are the main heating-chambers. a a are the surrounding walls of thefurnace. al al are the walls of the lire-pit. b b are the irebeds. c care walls forming vertical iiues d d. c e are the heating-hearths,formed by tiles or fire-brick. j' is the top of the furnace, built inthe form of an arch on the under and inner side of the furnace. .g g areopenings in the heating-hearth to the iiues d1 d1. a2 a2 aredivision-walls, forming, with the walls a and al, labyrinthical lues alld1, communicating with the iiues dz d2, formed within the side walls cof the furnace. -The iiues d3 d3 are formed at the junction of the topof the side walls a a with the top f of the furnace, communicating withthe iiues ZZ d2, and leading to the stack z'. The top covering m m ofthese lues d3 d3 are made adjustable for the purpose of admitting airinto the iiues for regulating the draft. The openings j j and doors k 7care also for regulating the draft of the furnace bythe admission of airat that point into the iiues. y

By the use of the labyrinthical lines d1 di the heat is brought intocontact with the hearths c c, andv by the increased length of the fluesthe draft is greatly increased.

I now proceed to describe the operation of my furnace. y

The caloric rises from the coals, and, by the draft of the flues, ismade to pass up, through the ues d d, against the archf of the chamberA, and is then made to descend, through the openin gs gg, into ltheiiues d1 d1, and up through the flues d2 cl2 and the flues d3 d3 to thestack i,

the draft being regulated, as above stated, by

.means of the movable tops m m of the fines d2,

and the openings j j and doors k k. The plates to be heated are placed011 the hearths of the furnace through the doors N N.

Having thus described my invention, what I claim, and desire to secureby Letters Patent, 1s-4 1. In a heating or tending furnace, thecombination, with the chamber A, the lvertical iiues d d, arch f,flue-openings g g, ue's d1 dl, d d2, and d3 d3, substantially asdescribed and shown.

2. In a heating or tending furnace, the heating-hearths c, incombination with the flue dl beneath the same, iiues d d, chamber A, andtheopenings g g, substantially as described and shown.

3. In a heating or tending furnace, the openings j j and doors k k,beneath the heatinghearths, substantially as described and shown.

In testimony that I claim the foregoing as my invention I hereto set myhand, at Pittsburg, Pennsylvania, this 18th day of October,

WILLIAM S. MOKENNA.

Witnesses:

JOHN H.. STEVENsoN, A. H. GEEENAWALT.

